This invention relates to the latching or securing of one component of subassembly to another, where the one component is frequently changed or interchanged in use; and more particularly to a mechanism and method wherein such latching or securing may be accomplished very quickly and effectively.
This invention may have application in a wide variety of apparatus or mechanisms. One example of apparatus for which the latching mechanism of the invention is well suited, is a hydraulic motor driven lead screw tapping unit of the type described in applicant's U.S. Pat. No. 4,050,835 granted Sept. 27, 1977. The tapping unit which is the subject of that patent is a production tapping unit having a main housing which is secured to a fixture and which, by means of a lead screw, drives a tap into and out of a prebored hole in a workpiece also secured to the fixture. In such tapping unit, the spindle subassembly includes a lead screw, a lead nut which is secured in a lead nut plate which must be secured to one end of the unit housing, a lead screw spindle tap chuck at the distal end of the spindle for mounting the tap. It is frequently necessary to change this spindle subassembly to accommmodate taps having different threads and where, of course, the lead of the lead nut and lead screw must be changed.
Also, in this type of unit, it may be necessary to frequently change the hydraulic drive motor for the unit. For one use of the unit, a high speed-low torque motor may be required; and for another use of the unit, a low speed-high torque motor may be required. Normally, such spindle subassemblies and motor subassemblies are secured to the main housing by means of several bolts; and the changing out of these subassemblies requires substantial time. This type of mounting may be necessary where there is a relative axial load between the subassembly and the main housing; however where there is substantially no axial load, or where there is no substantial axial load tending to separate the subassemblies from the main housing, a lower strength latching system may be employed.
An object of this invention is to provide an improved latching mechanism wherein a component may be released from a main body, and reassembled with a main body in a very short time.
Another object of this invention is to provide such a latching mechanism wherein a latching member is associated with a lever which by simple oscillation effects the release of the latching member and the reengagement of the latching member.
A further object of this inventionis to provide a quick change latching mechanism which includes a linear tension spring latching member.
Still another object of this invention is to provide such an improved latching mechanism which is effective and reliable.
Another object of this invention is to provide an improved and unique method for latching one component to another.
A further object of this invention is to provide an improved and unique method for very quickly latching two components together and for unlatching those components.
A still further object of this invention is to provide a novel method for latching and unlatching a pair of components which involves the simple movement of an oscillating lever.
Still another object of this invention is to provide a quick change latching mechanism which includes a stiff by elastic latching arm.
These objects are accomplished in a mechanism which includes a lever rotatably mounted on the first component for oscillation about an axis and a latching pin mounted on the second component. In the joined condition of the first and second components, the latching pin is disposed generally parallel with the axis of the oscillating lever and generally traversing the plane of oscillation of the lever. The lever includes a pivot mount for a latching member, which pivot mount is disposed eccentrically of the lever axis and includes a pivot axis which is parallel to the lever axis. The latching member is a linear tension spring having a pivot mount at one end, and having a hook at its other end configured to engage the latching pin. The latching member is frictionally mounted on the pivot mount of the lever, so that the latching member will normally oscillate with the lever. A stop means is mounted on the first component for limiting the oscillation of the lever in one direction; and this limit position of the lever defines the lock position for the lever wherein the tension of the spring latching member maintains the lever against the stop means. A stop means on the first component limits oscillation of the latching member away from the latch pin, when the lever is moved away from its locked position.
These objects are also accomplished in a method for latching a second component to a first component which includes the following steps. A lever is mounted on the first component for oscillation about an axis. One end of a linear tension spring latch member is mounted on that lever for frictional oscillation about an axis which is eccentric to and parallel to the lever axis. A latch pin is provided on the second component and is disposed, when the second component is in the joined condition with the first component, generally parallel with the lever axis and generally traversing the plain of oscillation of the lever.
The latch member is provided with a latch hook at its distal end for engagement with the latch pin. Oscillation of the lever is limited in one direction relative to the first component to define the latch position of the lever, wherein the lever is maintained in that limit position by the tension of the latch member. The oscillation of the latch member away from the latch pin is limited, during oscillation of the lever away from the lock position, to maintain the latch member in position to reengage the latch pin of a second component which is placed in the joined relation with the first component.
The novel features and the advantages of the invention, as well as additional objects thereof, will be understood more fully from the following description when read in connection with the accompanying drawings.